Manufacture of artificial materials



Patented May 23, 1939 UNITED STATES.

PATENT OFFICE No Drawing. Application April 2, 1937, Serial No. 134,527. In Great Britain April 29, 1936 3 Claims.

This invention relates to improvements in the manufacture of artificial materials and particularly to the production of yarns, fabrics and other textile materials, and of foils, films and the like containing organic derivatives of cellulose and having an improved resistance to heat and moi sture and other improved properties.

- In United States application S. Nos. 39,290, 39,-

289 and 39,288 filed September 5, 1935, and No.

101,428 filed September 18, 1936, there are described processes for the production of improved artificial materials wherein formed filaments, yarns, foils, films and similar materials having a basis of organic derivatives ofcellulose are esterified with acid anhydrides or other esterifying agents in the presence of suitable catalysts, particularly ferric chloride or other metallic chlorides together with hydrochloric acid. By the processes described in the above applications artiflcial filaments, yarns and other materials may be obtained which have an improved resistance to moisture and an increased ironing point and which have different affinities for dyestuffs and different solubilities from those of the starting For example, by acetylating cellulose materials.

acetate yarns with acetic anhydride in the presence of ferric chloride and hydrochloric acid .yarns may be obtained which have an improved ironing point and which are substantially or completely insoluble in acetone. z

I have now discovered that mixed yarns, fabrics and similar materials containing short or long lengths of filaments having a basis of cellulose acetate or other organic derivative of cellulose and other filaments, for example cotton fibres or regenerated cellulose filaments in short or long lengths, may be subjected to esterification as described in the above specifications, and that in this manner products having noveland im- 40 proved properties may be obtained. Preferably esterification is effected with'an anhydride of a lower fatty acid, i. e., an acid containing not more than six carbon atoms. Thus, for example,

yarns containing cotton or viscose filaments and cellulose acetate filaments in the form of staple fibre or long lengths may be treated in an acetylating bath containing acetic anhydride, ferric chloride and hydrogen chloride dissolved in benzene or carbon tetrachloride. Another method of '50 effecting esterification of a mixed material .con-

the catalyst by immersing it in benzene or carbon tetrachloride containing the catalyst.

I have further discovered that the properties of staple fibres of cellulose acetate or other organic derivative of cellulose and of spun yarn containing such fibresmay be improved, in a similar manner to those of continuous filaments of organic derivatives of cellulose by subjecting them to acetylation or other esterification as described in the specifications referred to above. Preferably esterification is effected with an anhydride of a lower fatty acid, i."e., an acid containing not more than six carbon atoms. Spun yarns may consist solely of fibres of cellulose acetate or other organic derivative of cellulose, or they may'contain also other constituents as, for example, cotton or other natural cellulosic fibres or regenerated cellulose fibres. The artificial staple fibres may have been obtained from ordinary yarn produced directly by a dry spinning operation, or from yarns which have been stretched, for example, in the presence of steam or'hot water as described in United States application S. Nos. 123,104, 123,105 and 123,106 filed January 30, 1937, 121,150, 121,151 and 121,152 filed January 18, 1937 and 17,242 filed April 19, 1935, or which may habe been shrunk or stretched and shrunk. The spun yarn may be produced directly from continuous filaments by the process described in United States application S. No. 23,- 804 filed May 28, 1935.

On account of their improved resistance to =moisture the products obtained'according to the processes described in the present specification and in United States application S. Nos. 39,290, 39,289 and 39,288 filed September 5, 1935, and No. 101,428 filed September 18, 1936, are particularly valuable for use in the insulation of electrical conductors or other electrical materials.

As described in prior specifications esterification may be carried out by means of an organic acid anhydride or an organic acid chloride. Further, esterification may also be effected by means of the organic acid itself in the presence of an organic acid anhydride. Preferably the organic acid is a lower fatty acid, i. e., an acid containing not more than six carbon atoms. For example yarns having a basis of an organic derivative of cellulose may be simultaneously acetylated and propionated by subjecting them to a treatment in the presence of one of the catalysts described in the above specifications using a medium containing acetic anhydride and propionic acid. Alternatively a mixed anhydride, preferably derived from lower fatty acids, for example acetic-propionic anhydride, maybe employed, or the materials may be impregnated with a medium containing the organic acid or anhydride, if desired in sufiicient concentration to effect swelling, and the impregnated materials may then be esterified in a medium containing the anhydride or the acid respectively. Again, the materials maybe reacted with a lower fatty acid or other organic acid with the aid of an anhydride, such as chloracetic anhydride or methoxy-acetic anhydride, which does not itself esterify under the conditions employed'. The medium may contain an organic acid or anhydride or other substance, e. g. methylene chloride, in sufiicient concentration to effect swelling of the materials. Thus cellulose acetate materials may be esterified in a medium containing 25-35% of methylene chloride dissolved in benzene or carbon tetrachloride.

The following examples illustrate the invention but'are not to be regarded as limiting it.

Example 1 A mixed yarn containing viscose filaments and stretched cellulose acetate filaments is treated for 1 to 2 hours in a bath containing 600 parts by weight of carbon tetrachloride, 90 parts by weight of acetic anhydride, about .8 part by weight of Example 2 A spun yarn made of cellulose acetate staple fibres is treated for about an hour in a medium consisting of about 800 parts of benzene, 100 parts of acetic anhydride, one part of crystallised ferric chloride and .5 part of hydrogen chloride. The yarn is then removed, washed first with benzene and then with water and dilute alkali to remove traces of acid and dried. It is found to have an increased acetyl value, a considerably reduced solubility in acetone, an improved resistance to ironing and treatment with hot aqueuous media and a decreased afiinity for the ordinary cellulose acetate dyestuffs.

Example 3 Cellulose acetate yarn is treated in a medium consisting of about 600 parts by weight of carbon tetrachloride, 110 parts by weight of glacial acetic acid, 130 parts by weight of chloracetic anhydride, .8 part by weight of acetyl chloride and .6 part by weight of anhydrous ferric chloride. After about an hour it is removed, washed first with carbon tetrachloride then with water and dilute alkali and dried. Its properties are similar to those of the product obtained according to Example 2.

Having described my invention what I desire to secure by Letters Patent is: t

1. Process for improving the properties of mixed yarns, fabrics and other textile materials containing filaments having a basis of organic derivatives of cellulose and filaments of regenerated cellulose of the viscose type, which comprises subjecting the materials to esterification with approximately 90 parts of an organic acid anhydride containing not more than six carbon atoms in a liquid medium which is a non-solvent for the materials, about 0.8 part of acetyl chloride, using a metal halide selected from the group consisting of iron, tin and zinc halides as a catalyst in an amount equivalent to about 0.6 part of anhydrous 'ferric chloride, the regenerated cellulose filaments being substantially unaffected by the esterifying agents.

2. Process for improving the properties of mixed yarns, fabrics and other textile materials containing filaments having a basis of cellulose acetate and filaments of regenerated cellulose of the viscose type, which comprises subjecting the materials to esterification with approximately 90 parts of an organic acid ar hydride containing not more than six carbon atoms in a liquid medium which is a non-solvent for the materials, about 0.8 part of acetyl chloride, using a metal halide selected from the group consisting of iron, tin and zinc halides as a catalyst in an amount equivalent to about 0.6 part of anhydrous ferric chloride, the regenerated cellulose filaments being substantially unafiected by the esterifying agents.

*3. Process .for improving the properties of mixed yarns, fabrics and other textile materials containing filaments having a basis of cellulose acetate and filaments of regenerated cellulose of the viscose type, which comprises subjecting the materials to acetylation with approximately parts of acetic anhydride, in a liquid medium which is a non-solvent for the materials, about 0.8 part of acetyl chloride, and about 0.6 part of anhydrous ferric chloride as a catalyst, the regenerated cellulose filaments being substantially unaflected by the acetylating agents.

' HENRY DREYFUS.

CERTIFICATE OF CORRECTION. Patent No. 2,159,015. May 25, 1959.

' HENRY DREXFUS.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1, first column, line 5L for the Word "of" read or; same page, second column, line 27 for "may habe" read have; line 55, for the word "application" read applications; and that the said Letters Patent should be read with this correction therein that the same may to the recordof the casein the Patent Office.

Signed and sealed thisllth day of July, A. D. 1939.

Henry Van Arsdale (Seal) Acting Commissioner of Patents. 

